1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
  4 */
  5
  6#include <linux/module.h>
  7#include <linux/of_address.h>
  8#include <linux/platform_device.h>
  9#include <linux/thermal.h>
 10
 11struct thermal_mmio {
 12	void __iomem *mmio_base;
 13	u32 (*read_mmio)(void __iomem *mmio_base);
 14	u32 mask;
 15	int factor;
 16};
 17
 18static u32 thermal_mmio_readb(void __iomem *mmio_base)
 19{
 20	return readb(mmio_base);
 21}
 22
 23static int thermal_mmio_get_temperature(struct thermal_zone_device *tz, int *temp)
 24{
 25	int t;
 26	struct thermal_mmio *sensor = tz->devdata;
 27
 28	t = sensor->read_mmio(sensor->mmio_base) & sensor->mask;
 29	t *= sensor->factor;
 30
 31	*temp = t;
 32
 33	return 0;
 34}
 35
 36static const struct thermal_zone_device_ops thermal_mmio_ops = {
 37	.get_temp = thermal_mmio_get_temperature,
 38};
 39
 40static int thermal_mmio_probe(struct platform_device *pdev)
 41{
 42	struct resource *resource;
 43	struct thermal_mmio *sensor;
 44	int (*sensor_init_func)(struct platform_device *pdev,
 45				struct thermal_mmio *sensor);
 46	struct thermal_zone_device *thermal_zone;
 47	int ret;
 48	int temperature;
 49
 50	sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
 51	if (!sensor)
 52		return -ENOMEM;
 53
 54	resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 55	sensor->mmio_base = devm_ioremap_resource(&pdev->dev, resource);
 56	if (IS_ERR(sensor->mmio_base))
 57		return PTR_ERR(sensor->mmio_base);
 58
 59	sensor_init_func = device_get_match_data(&pdev->dev);
 60	if (sensor_init_func) {
 61		ret = sensor_init_func(pdev, sensor);
 62		if (ret) {
 63			dev_err(&pdev->dev,
 64				"failed to initialize sensor (%d)\n",
 65				ret);
 66			return ret;
 67		}
 68	}
 69
 70	thermal_zone = devm_thermal_of_zone_register(&pdev->dev,
 71						     0,
 72						     sensor,
 73						     &thermal_mmio_ops);
 74	if (IS_ERR(thermal_zone)) {
 75		dev_err(&pdev->dev,
 76			"failed to register sensor (%ld)\n",
 77			PTR_ERR(thermal_zone));
 78		return PTR_ERR(thermal_zone);
 79	}
 80
 81	thermal_mmio_get_temperature(thermal_zone, &temperature);
 82	dev_info(&pdev->dev,
 83		 "thermal mmio sensor %s registered, current temperature: %d\n",
 84		 pdev->name, temperature);
 85
 86	return 0;
 87}
 88
 89static int al_thermal_init(struct platform_device *pdev,
 90			   struct thermal_mmio *sensor)
 91{
 92	sensor->read_mmio = thermal_mmio_readb;
 93	sensor->mask = 0xff;
 94	sensor->factor = 1000;
 95
 96	return 0;
 97}
 98
 99static const struct of_device_id thermal_mmio_id_table[] = {
100	{ .compatible = "amazon,al-thermal", .data = al_thermal_init},
101	{}
102};
103MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
104
105static struct platform_driver thermal_mmio_driver = {
106	.probe = thermal_mmio_probe,
107	.driver = {
108		.name = "thermal-mmio",
109		.of_match_table = thermal_mmio_id_table,
110	},
111};
112
113module_platform_driver(thermal_mmio_driver);
114
115MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
116MODULE_DESCRIPTION("Thermal MMIO Driver");
117MODULE_LICENSE("GPL v2");